A real-time sound feedback device and method based on gait event triggering

Abstract

The application discloses a real-time sound feedback method and equipment based on gait event triggering and belongs to the field of walking cognitive experiment equipment. The equipment comprises a sensing unit, a lower computer, an upper computer and a sound conveying system; the sensing unit comprises a pressure sensor installed in a shoe cover and dispersedly transmitting pressure by a hard foam pad, the heel of a subject rhythmically presses the hard foam pad during walking, and the sensing area of the pressure sensor and the protective film are kept in a detachable pressure contact during the heel strike; the lower computer collects the voltage signal output by the pressure sensor in real time, maps the voltage signal into a standard pressure value and then transmits the standard pressure value to the upper computer in real time, the upper computer analyzes the standard pressure data stream, and when it is determined that the heel strike event occurs, the upper computer immediately controls the sound conveying system to emit sound stimulation with a preset frequency, amplitude and time length. The application provides a multimodal platform interconnection and closed-loop system integration scheme and can provide support for psychology and cognitive neuroscience research.

Description

Technical Field

[0001] This invention belongs to the field of walking cognition experimental equipment, specifically relating to a real-time sound feedback device and method based on gait event triggering. Background Technology

[0002] Walking, as one of the most basic human activities, relies on the coordinated use of multiple senses for stability. Especially in unfamiliar and complex environments, hearing plays a crucial role: the human body adjusts its gait in real time to maintain balance and avoid risks by listening to environmental sounds and the sounds produced by its own movements (such as footsteps).

[0003] When processing auditory information, the brain does not passively receive it, but constantly makes "active predictions." Predictive processing theory states that the brain predicts upcoming sensory input (such as the sound of footsteps) based on previous experience. When the actual sound matches the prediction, the brain assumes the "prediction is accurate" and reduces the processing intensity of that information, thus conserving cognitive resources. If there is a discrepancy (such as the sound suddenly disappearing or changing pitch), a "prediction error" occurs, immediately attracting the brain's attention and prompting it to update its predictive model.

[0004] Walking itself possesses a stable rhythm, with the alternating steps of the legs forming a predictable periodic movement. Each step not only produces a real footstep sound but also activates the prediction of the next footstep sound. This "prediction-feedback" cycle makes walking an ideal way to study auditory prediction mechanisms.

[0005] To delve deeper into how the brain processes such prediction errors, electroencephalography (EEG) has become a key tool due to its millisecond-level temporal resolution. This technology records brain neural activity using non-invasive scalp electrodes, capturing event-related potential components associated with auditory processing. Among these, the N1 component, appearing approximately 100 milliseconds after a sound stimulus, is considered a crucial indicator, as its amplitude changes directly reflect the intensity of the brain's neural response to sound prediction errors. In specific experiments, prediction errors can be actively induced by intentionally altering or canceling the predicted sound at the moment the foot touches the ground. By analyzing the amplitude changes of the N1 component at this time, the neural mechanisms by which the brain processes prediction errors and regulates perception during natural walking can be effectively revealed.

[0006] However, existing plantar pressure gait systems have key limitations, making them difficult to apply to auditory predictive coding research in natural walking. Existing plantar pressure-based gait sensing systems mainly consist of a piezoresistive pressure sensor for measuring plantar pressure, an insole or shoe housing the pressure sensor, a microcontroller for acquiring plantar pressure data, and an application terminal for displaying the plantar pressure data. These systems have the following limitations:

[0007] 1. Insufficient sensor design and data reliability: Existing devices mainly rely on pressure sensor arrays embedded in the insole or inside the shoe to collect the pressure distribution of the sole. This design has inherent limitations: if the sensor is placed inside the shoe, it is easily squeezed by various parts of the shoe to generate irrelevant pressure signals, which interfere with the accuracy of real gait data; if the sensor is directly exposed to the ground, it can usually only obtain static data and it is difficult to effectively capture the continuous pressure changes during dynamic walking.

[0008] 2. Insufficient data acquisition and synchronization: Existing devices typically transmit data to terminal applications or memory cards via Bluetooth. A key drawback is that this transmission method struggles to achieve real-time interconnection with specialized research software such as MATLAB and Lab Streaming Layer, and it particularly lacks precise and unified timestamp synchronization and event tagging capabilities. This makes it impossible to meet the research requirements for strict synchronization of multimodal data (such as neurophysiological signals and gait events).

[0009] 3. Lack of gait event recognition function: The existing system functions mainly focus on plantar pressure distribution assessment, which cannot identify key gait events (such as the precise moment of heel strike or lift-off) in real time and accurately. Therefore, it is difficult to accurately trigger auditory stimuli in specific gait events to explore predictive processing mechanisms.

[0010] 4. Lack of integrated systems: Currently, there is a lack of integrated systems and devices that can simultaneously achieve high-precision gait information acquisition, trigger sound stimuli at precise gait events, and interconnect with multiple software platforms and devices in real time. Summary of the Invention

[0011] The purpose of this invention is to solve the problems existing in the prior art and to provide a real-time sound feedback device and method based on gait event triggering.

[0012] The specific technical solution adopted in this invention is as follows:

[0013] In a first aspect, the present invention provides a real-time sound feedback device based on gait event triggering, which includes a sensing unit, a lower-level computer, a higher-level computer, and a sound transmission system;

[0014] The sensing unit includes a pressure sensor, a shoe cover, and a rigid foam pad. The shoe cover is used to cover the sole of the test subject's shoe. A protective film is attached to the inside of the shoe cover at the position corresponding to the heel. The top surface of the pressure sensor is attached and fixed to the bottom of the rigid foam pad. The area of ​​the rigid foam pad not covered by the pressure sensor is fixed to the shoe cover. During the test subject's walking, the heel rhythmically applies pressure to the rigid foam pad. During the heel strike, the sensing area of ​​the pressure sensor and the protective film maintain a detachable pressure contact.

[0015] The lower-level machine is connected to the pressure sensor in the sensing unit and the upper-level machine respectively. The lower-level machine collects the voltage signal output by the pressure sensor in real time, maps it to a standard pressure value and transmits it to the upper-level machine in real time. The upper-level machine is connected to the sound transmission system.

[0016] The sound transmission system is worn on the ears of the test subjects and has sound insulation and sound transmission functions;

[0017] The host computer analyzes the received standard pressure data stream and uses the latest collected standard pressure value falling within the pressure response range corresponding to the heel strike event as the first judgment condition. The second judgment condition is that the difference between the average standard pressure in the most recent time window and the average standard pressure in the previous time window is less than a negative threshold close to 0. When both judgment conditions are met, it is determined that a heel strike event has occurred, and the computer immediately controls the sound transmission system to emit sound stimuli with a preset frequency, amplitude, and duration.

[0018] As a preferred embodiment of the first aspect above, the pressure sensor is a piezoresistive pressure sensor, whose output voltage signal is negatively correlated with the applied pressure; after the lower-level computer collects the voltage signal output by the pressure sensor in real time, it standardizes and maps it into an 8-bit binary standard pressure value, and then transmits it to the upper-level computer in real time in the form of a binary data stream.

[0019] As a preferred embodiment of the first aspect above, the range of the standard pressure value is [0, 255], and in the first determination condition, the lower limit of the pressure response interval is 215~230, and the upper limit is 240~255.

[0020] As a preferred embodiment of the first aspect above, the range of the standard pressure value is [0, 255], the time window size in the second determination condition covers 3 to 8 standard pressure value data points, and the negative threshold value is between -1 and -5.

[0021] As a preferred embodiment of the first aspect above, the sound transmission system consists of a sound card and noise-isolating headphones. The host computer sends instructions to the sound card, which then drives the noise-isolating headphones to emit sound stimuli with a preset frequency, amplitude, and duration.

[0022] As a preferred embodiment of the first aspect, the outer surface of the shoe cover that contacts the ground is made of a sound-absorbing material.

[0023] As a preferred embodiment of the first aspect, the communication between the lower-level computer and the pressure sensor, between the lower-level computer and the upper-level computer, and between the upper-level computer and the sound transmission system are all conducted via wired transmission.

[0024] As a preferred embodiment of the first aspect, the lower-level computer, the upper-level computer, and the sound transmission system are all integrated into the backpack, and a retractable cable is used between the lower-level computer and the sensing unit, with an ergonomic cable routing scheme to eliminate cable entanglement interference during walking.

[0025] As a preferred embodiment of the first aspect, it further includes a head-mounted EEG acquisition device that is communicatively connected to the host computer, used to acquire EEG signals of the subject during walking.

[0026] Secondly, the present invention provides a method for collecting walking cognitive experiment data using a real-time sound feedback device as described in any of the first aspects above, the specific steps of which are as follows:

[0027] The shoe cover from the sensing unit was placed over the sole of one of the subjects' shoes, and the head-mounted EEG acquisition device was worn on the subject's head.

[0028] During the walking process, the heel rhythmically applied pressure to the rigid foam pad, and the sensing area of ​​the pressure sensor and the protective film maintained a detachable pressure contact during heel strike.

[0029] The lower-level computer collects voltage signals in real time, processes them into a standard pressure data stream, and then transmits it to the upper-level computer for storage and analysis.

[0030] During the subject's walking process, the host computer detects the occurrence of a heel strike and immediately controls the sound transmission system to execute corresponding sound stimuli according to the frequency, amplitude, and duration specified in the preset auditory stimulation paradigm. Simultaneously, during the subject's walking process, the head-mounted EEG acquisition device collects the subject's EEG signals in real time and stores them synchronously in the host computer.

[0031] Compared with the prior art, the present invention has the following advantages:

[0032] 1) This invention provides a high-precision, anti-interference pressure sensing design. This design utilizes an innovative sandwich layout, placing the pressure sensor between the heel of the shoe and the top of the shoe cover, forming a five-layer structure: heel of the shoe, rigid foam pad, pressure sensor, protective layer, and shoe cover. This structure allows the protective film to separate from the sensing area of ​​the pressure sensor under the weight of the shoe cover when the foot is suspended in the air, thus completely eliminating irrelevant pressure noise interference during the lift-off and landing cushioning periods, ensuring accurate capture of the pressure signal triggered by the heel strike. This shoe cover design also provides physical protection against impact and abrasion for the sensor, extending the device's lifespan.

[0033] 2) This invention provides a millisecond-level heel strike event recognition and closed-loop triggering algorithm. This algorithm combines static range judgment conditions and dynamic change judgment conditions, which can verify that the signal is in the effective response range while capturing the unique pressure characteristics of the heel strike event, thereby accurately identifying the heel strike event. Its real-time detection performance reaches the millisecond level.

[0034] 3) This invention provides a highly stable microsecond-level real-time pressure data transmission scheme. In this scheme, the lower-level computer directly reads the original value of the ADC register and converts it into a standard pressure value. Then, it uses a wired transmission architecture to upload the data to the upper-level computer in real time. The transmission time jitter error is less than 1μs, which can overcome the latency and packet loss bottleneck of the traditional Bluetooth scheme and ensure the stability and timeliness of the data stream received by the upper-level computer.

[0035] 4) This invention provides a multimodal research platform interconnection and closed-loop research system integration scheme. This scheme constructs a complete gait-auditory feedback experimental system that can natively connect to research software such as MATLAB and Lab Streaming Layer, and can timestamp and synchronize the clocks of devices such as EEG and breathing belts to achieve seamless real-time data flow interaction. It can also provide innovative tools for research in psychology and cognitive neuroscience, for example, it can be applied to the study of the regulatory mechanism of auditory prediction on sensory processing during walking. Attached Figure Description

[0036] Figure 1 This is a schematic diagram illustrating the usage status of a real-time sound feedback device triggered by gait events.

[0037] Figure 2 This is a schematic diagram of the sensing unit.

[0038] Figure 3 This is a schematic diagram of the control logic of the device of the present invention;

[0039] Figure 4 This is a visualization of the time between the standard plantar pressure value collected by the pressure sensor in the sensing unit of the present invention during walking and the sound playback triggered by the algorithm of the present invention.

[0040] Figure 5 for Figure 4 Visualization results of the time accuracy of the pressure data in the data (1kHz sampling rate, microsecond-level accuracy);

[0041] Figure 6 This is a visualization of the average N1 component amplitude differences in EEG data collected from all subjects at the moment of footsteps landing under different auditory stimuli (standard, exotic, and silent).

[0042] Figure 7 Schematic diagrams of two pressure sensor arrangement schemes used as a comparison;

[0043] Figure 8 This is a visualization of the standard plantar pressure value collected by the pressure sensor in the sensing unit of the present invention during walking.

[0044] Figure 9 This is a visualization of the standard pressure values ​​collected by the pressure sensor in the sensing unit of control experiment A during walking.

[0045] Figure 10 This is a visualization of the standard pressure values ​​collected by the pressure sensor in the sensing unit of control experiment B during walking.

[0046] The attached figures are labeled as follows: Sensing unit 1, Lower computer 2, Upper computer 3, Sound transmission system 4, Head-mounted EEG acquisition device 5, Shoe cover 101, Protective film 102, Pressure sensor 103, Rigid foam pad 104, Wiring terminal 105, Shoe 106. Detailed Implementation

[0047] To make the above-mentioned objects, features, and advantages of the present invention more apparent and understandable, specific embodiments of the present invention will be described in detail below with reference to the accompanying drawings. Many specific details are set forth in the following description to provide a thorough understanding of the present invention. However, the present invention can be practiced in many other ways different from those described herein, and those skilled in the art can make similar modifications without departing from the spirit of the present invention. Therefore, the present invention is not limited to the specific embodiments disclosed below. Technical features in various embodiments of the present invention can be combined accordingly without mutual conflict.

[0048] In the description of this invention, it should be understood that when an element is considered to be "connected" to another element, it can be a direct connection to the other element or an indirect connection, i.e., there is an intermediate element. Conversely, when an element is said to be "directly" connected to another element, there is no intermediate element.

[0049] In the description of this invention, it should be understood that the terms "first" and "second" are used only for descriptive purposes and should not be construed as indicating or implying relative importance or implicitly specifying the number of indicated technical features. Therefore, a feature defined as "first" or "second" may explicitly or implicitly include at least one of that feature.

[0050] like Figure 1As shown, in a preferred embodiment of the present invention, a real-time sound feedback device based on gait event triggering is provided. Its components include a sensing unit 1, a lower-level computer 2, a higher-level computer 3, and a sound transmission system 4. This device is a complete gait-sound feedback system that can be used to conduct experiments in psychology and cognitive neuroscience, such as investigating the impact of footstep-induced auditory prediction on auditory processing, or investigating the moderating effect of walking motion itself on prediction error. The specific structural implementation and working principle of each component of the above-mentioned real-time sound feedback device based on gait event triggering are described in detail below.

[0051] like Figure 2 As shown, the aforementioned sensing unit 1 includes a shoe cover 101, a pressure sensor 103, and a rigid foam pad 104. The shoe cover 101 is used to cover the bottom of the shoe 106 worn by the test subject. To ensure that the shoe cover 101 does not cause interference noise when it hits the ground, the outer surface of the shoe cover 101 in contact with the ground needs to be made of a sound-absorbing material. A preferred approach is to cover the outside of the shoe cover 101 with a layer of fleece shoe cover to reduce the friction noise generated by walking on the ground. Inside the shoe cover 101, a protective film 102 is attached to the position corresponding to the contact with the heel using glue or the like. The top surface of the pressure sensor 103 is attached and fixed to the bottom of the rigid foam pad 104, and the sensing area of ​​the pressure sensor 103 only covers the heel pressure area of ​​the rear half of the bottom of the rigid foam pad 104, while the area of ​​the front half of the midsole of the rigid foam pad 104 that is not covered by the pressure sensor 103 is fixed to the shoe cover 101. The area where the top surface of the protective film 102 contacts the sensing area of ​​the pressure sensor 103 is non-adhesive, allowing for flexible contact and detachment. The bottom surface of the rigid foam pad 104 is flat, and its top surface fits snugly against the sole, thus evenly distributing the pressure transmitted from the shoe 106 to the pressure sensor 103. The pressure sensor 103 is a piezoresistive pressure sensor, whose output voltage signal is negatively correlated with the applied pressure. The wiring of the pressure sensor 103 passes through the gap between the rigid foam pad 104 and the protective film 102, and exits through a pre-drilled hole in the shoe cover 101, with the terminal 105 located outside the shoe cover.

[0052] The model of the pressure sensor 103 can be selected according to actual needs. In the embodiment of the present invention, a piezoresistive pressure sensor of model IMS005-C40A can be used. This pressure sensor has a minimum measuring force of 500 grams, a sensor range of 10 kilograms, and an excitation resistance > 2 Mega Ohms.

[0053] In the sensing unit 1 of the present invention, the shoe cover is worn over the sole of the left or right foot of the test subject. When the heel strikes the ground, the heel applies pressure to the pressure sensor 103 through the rigid foam pad 104, causing the pressure sensor 103 to receive a pressure signal. During the test subject's walking, the heel rhythmically applies pressure to the rigid foam pad 104. However, due to the presence of the protective film 102, the sensing area of ​​the pressure sensor 103 maintains a detachable pressure contact with the protective film during heel strike. That is, when pressure is applied, the pressure sensor 103 adheres to the protective film 102, but when the heel is lifted, the sensing area of ​​the pressure sensor 103 can immediately separate from the protective film 102. Since there is a non-adhesive protective film 102 on the top surface between the sensing area of ​​the pressure sensor 103 and the shoe cover, the pressure sensor's pressure-bearing area will not stick to the shoe cover, allowing the pressure sensor 103 to immediately return to its original state when the heel is suspended in the air, without being interfered with by other pressures. Compared to the traditional approach of placing pressure sensors inside the shoe or attaching them to the sole, this sensing unit 1, through a redesigned foot pressure sensor layout, effectively eliminates interference from irrelevant pressure inside the shoe, ensuring the real-time, accuracy, and reliability of gait information, especially heel strike events, during dynamic walking and standing.

[0054] It should be noted that the aforementioned sensing unit 1 only needs to be fitted onto one of the feet, that is, the pressure sensor 103 can be placed on either the left or right foot.

[0055] The lower-level computer 2 of this invention is connected in communication with the pressure sensor in the sensing unit 1 and the upper-level computer 3. The lower-level computer 2 collects the voltage signal output by the pressure sensor in real time, maps it to a standard pressure value, and transmits it to the upper-level computer 3 in real time. The upper-level computer 3 also needs to be connected in communication with the sound transmission system 4. The sound transmission system 4 is worn on the ear of the test subject and has the functions of isolating external noise and playing a specified sound to the test subject.

[0056] In an embodiment of the present invention, the lower-level machine 2 can be implemented using an Arduino Due development board, which has built-in necessary signal processing and conversion units such as an analog-to-digital converter (ADC). The Arduino Due development board is connected to a signal amplifier, which is connected to the terminals of the pressure sensor. Thus, the Arduino Due directly reads the original voltage signal V from its internal ADC register at a sampling rate of 1kHz through an interrupt service routine. ADC The Arduino Due development board acquires the voltage signal V. ADC This can then be mapped to a standard pressure value in 8-bit binary form. (Corresponding to the decimal value range of 0~255), the mapping formula is:

[0057]

[0058] The original voltage signal in the ADC register This corresponds to the amplified analog voltage; This indicates rounding down to the nearest integer. Plantar pressure and... The values ​​are negatively correlated, meaning that when the pressure increases... The value decreases.

[0059] In embodiments of the present invention, the host computer 3 can be a miniature computer. An Arduino Due acquires the voltage signal output from the pressure sensor in real time and normalizes and maps it to an 8-bit binary standard pressure value. After the data stream is received, it can be transmitted to the host computer 3 in real time via the communication unit. To ensure the real-time performance of data transmission, communication between the lower computer 2 and the pressure sensor, and between the lower computer 2 and the host computer 3, needs to be conducted via wired transmission. This minimizes latency and avoids packet loss, ensuring the timeliness and stability of the data stream received by the host computer 3.

[0060] The host computer 3 of this invention needs to be equipped with software programs to analyze the received standard pressure data stream. Software such as Lab Streaming Layer and MATLAB can be pre-installed on the host computer 3. MATLAB is responsible for real-time data analysis, and Lab Streaming Layer is responsible for persistent data storage. Of course, Lab Streaming Layer and MATLAB are only recommended software programs; theoretically, other data analysis and storage software programs can also be used.

[0061] Based on the needs of walking cognition experiments, the key point of the analysis of standard pressure data stream in the host computer 3 of this invention is to determine in real time whether a heel strike event occurs. Once a heel strike event occurs, specific sound stimuli need to be played according to the experimental paradigm. In specific experiments, the sound frequency can be intentionally changed or the sound stimulus can be canceled at the moment the foot touches the ground, thereby actively inducing prediction errors in the brain. By analyzing the amplitude changes of the N1 component at this time, the neural mechanisms by which the brain processes prediction errors and regulates perception under natural walking conditions can be effectively revealed.

[0062] Therefore, based on the above requirements, this invention designs a dual-threshold decision algorithm to capture heel strike events. This algorithm sets two threshold judgment conditions: the first condition is that the latest collected standard pressure value falls within the pressure response range corresponding to the heel strike event; the second condition is that the difference between the average standard pressure value in the most recent time window and the average standard pressure value in the previous time window is less than a negative threshold close to 0. A heel strike event is determined to have occurred when both conditions are met simultaneously. The first condition is a static pressure range judgment condition, used to verify that the pressure signal is within the effective response range, while the second condition is a dynamic pressure change judgment condition, used to capture the unique pressure change characteristics of heel strike events, i.e., the standard pressure value... It starts to fall back from its maximum value.

[0063] It is important to note that the pressure response interval, specific time window, and negative threshold size corresponding to the heel strike event can all be optimized based on the actual situation. Preferably, the aforementioned "most recent time window" and "previous time window" are adjacent but do not overlap.

[0064] Therefore, the mathematical expression for determining the occurrence of a heel strike event is as follows:

[0065]

[0066] In the formula: This represents the latest sampled standard pressure value, where n is the index of the corresponding data point in the stored standard pressure value data stream. The standard pressure value at the i-th data point in the standard pressure value data stream represents the stored standard pressure value. and These represent the lower and upper limits of the pressure response range, respectively. This represents the size of the time window, i.e., the number of standard pressure data points covered. The threshold representing negative numbers close to 0; This indicates a logical AND operation, meaning that a heel-to-spot event is determined only if both conditions are met.

[0067] In an embodiment of the present invention, if the aforementioned standard pressure value The value range is [0, 255]. Therefore, in the first judgment condition, the lower limit of the pressure response interval is... The preferred value is 215~230, with an upper limit. The optimal value is 240~255. Simultaneously, the time window in the second determination condition... The optimal size covers 3-8 standard pressure data points, with a negative threshold. The optimal size is between -1 and -5. The specific values ​​of each parameter can be fine-tuned according to the body weight and actual conditions.

[0068] The parameters in the above threshold judgment condition can be further optimized. , , , Therefore, the two corresponding threshold judgment conditions are:

[0069] (i) Determination of static pressure range:

[0070] (ii) Dynamic change determination: The latest 5 consecutive data points ( arrive The arithmetic mean of ) and the previous 5 consecutive data points ( arrive The difference between the arithmetic means of ) is less than -1.

[0071] If both threshold conditions (i) and (ii) are met simultaneously, it can be determined that a heel strike event has occurred. The mathematical expression for this dual threshold condition is as follows:

[0072]

[0073] In an embodiment of the present invention, the judgment process can be executed by MATLAB. Once the host computer 3 detects that two judgment conditions are met at the same time, it can be determined that a heel-to-toe event has occurred. At this time, it is necessary to immediately control the sound transmission system 4 to send sound stimuli with preset frequency, amplitude and duration to the subject.

[0074] In an embodiment of the present invention, the sound transmission system 4 consists of a sound card and noise-isolating headphones. The host computer 3 immediately sends instructions to the sound card, which then drives the noise-isolating headphones to emit sound stimuli with a preset frequency, amplitude, and duration. Similarly, to ensure real-time sound playback, the host computer 3, the sound card, and the headphones also need to communicate via wired transmission.

[0075] Therefore, as Figure 3 As shown, the overall method logic in this invention is as follows: The Arduino Due acquires the voltage signal output by the pressure sensor in real time and maps it into a standard pressure value. The data stream is then transmitted to host computer 3 in real time, and host computer 3 receives it in real time. The data stream is handled by two mechanisms: persistent data storage by the Lab Streaming Layer and real-time data analysis by MATLAB. MATLAB determines whether the two threshold conditions are met simultaneously. If both conditions are met, MATLAB issues a real-time command, which is transmitted to the sound card via an interface. The sound card receives the playback command from MATLAB and immediately outputs the sound to the headphones for playback, then proceeds to the next test. If either threshold condition is not met, the system continues to collect and analyze updated stress data.

[0076] Since the experimental scenario of this invention requires subjects to continuously walk to collect data, in the embodiments of this invention, see... Figure 1 The lower-level computer 2, upper-level computer 3, and sound transmission system 4 can all be integrated into the backpack. A retractable cable connects the lower-level computer 2 and the sensing unit 1, and an ergonomic cable routing scheme eliminates cable entanglement interference during walking. Specifically, the retractable cable between the lower-level computer 2 and the sensing unit 1 can be a spring-loaded, stretchable cable. After passing through the shoe cover, the cable can be secured to the lower leg with a buckle strap, eliminating cable entanglement interference during walking, maintaining a natural gait, and ensuring the ecological validity of the experiment.

[0077] Furthermore, since different test subjects have different shoe sizes, multiple sizes of shoe covers can be provided. The pressure sensor is detachably installed in sensing unit 1, supporting reuse in different sized shoe covers. The pressure sensor can be removed individually or together with the rigid foam pad. This design allows for quick replacement of shoe covers to fit different sizes, improving equipment reusability and maintenance efficiency.

[0078] Furthermore, the aforementioned real-time sound feedback device triggered by gait events can be used in conjunction with EEG, breathing belts, and other equipment to collect more complex walking cognitive experimental data in practical applications. (See also...) Figure 1 As shown in the embodiment of the present invention, the real-time sound feedback device further includes a head-mounted EEG acquisition device 5, used to acquire EEG signals during the subject's walking process. The head-mounted EEG acquisition device 5 can communicate with the host computer 3, and data acquired by different devices can be stored together in the host computer 3, and used for subsequent research and analysis after aligning the timestamps through the Lab Streaming Layer.

[0079] Therefore, based on the aforementioned real-time sound feedback device integrating a head-mounted EEG acquisition device, this invention provides a method for collecting data in a walking cognition experiment, the specific steps of which are as follows:

[0080] S1. Place the shoe cover from sensing unit 1 over the outside of the sole of one foot (left or right foot) of the subject, and then place the head-mounted EEG acquisition device on the subject's head.

[0081] S2. During the subject's walking process, the heel rhythmically applies pressure to the rigid foam pad, and the sensing area of ​​the pressure sensor maintains detachable pressure contact with the protective film during heel strike. During this process, the lower-level computer 2 collects voltage signals in real time, processes them into a standard pressure data stream, and transmits it to the upper-level computer 3 for storage and analysis. During the subject's walking process, the upper-level computer 3 determines that a heel strike event has occurred and immediately controls the sound transmission system 4 to execute corresponding sound stimuli according to the frequency, amplitude, and duration specified in the preset auditory stimulation paradigm. Simultaneously, during the subject's walking process, a head-mounted EEG acquisition device collects the subject's EEG signals in real time and stores them synchronously in the upper-level computer 3 for data analysis.

[0082] To demonstrate the practical application effect of the real-time sound feedback device based on gait event triggering described in this embodiment of the invention, signal data uploaded by each unit to the host computer was collected through an actual walking cognition experiment. The various data were aligned according to timestamps and then visualized. Figure 4 This demonstrates the standard plantar pressure values ​​during the subjects' walking process. The timing of the sound card being triggered by the algorithm of this invention demonstrates that the device can accurately trigger the sound at the moment the foot touches the ground, ensuring accuracy and timeliness. Figure 5 Showing Figure 4 The time accuracy results of the collected pressure data show that the time accuracy of the pressure data collected by this device can reach the microsecond level.

[0083] Furthermore, this invention designs an auditory stimulation paradigm in a walking cognition experiment, which includes three stimulation conditions: standard stimulus, exotic stimulus, and silent stimulus. The experiment consisted of 2000 randomized trials, with standard stimulus accounting for 90%, and exotic and silent stimuli each accounting for 5%. In the standard stimulus trials, whenever the host computer detected a heel strike, it immediately played a pure tone with a duration of 75ms and a frequency of 1000Hz to the participants, with its intensity (i.e., amplitude) set to a constant level that all participants could clearly perceive. In the exotic stimulus trials, the heel strike immediately triggered a pure tone with a duration of 75ms and a frequency of 1280Hz, with the same intensity as the standard stimulus. In the silent stimulus trials, no sound was played after the heel strike was detected. Simultaneously, due to the sound insulation effect of the headphones and the noise-absorbing properties of the shoe covers, the faint footstep sound originally produced by the shoes landing was also isolated. Figure 6This study presents the differences in the mean amplitude of the N1 component in EEG data collected from 26 subjects under three different auditory stimulation conditions; the zero point of latency corresponds to the moment of heel strike. The results show that after heel strike, the N1 amplitude induced by the exotic stimulus was significantly greater than that under the standard stimulus condition, while the N1 amplitude was smallest under the condition without auditory stimulation.

[0084] Finally, in order to prove this invention Figure 2 The advantages of the sensing unit, shown in the five-layer structure of the shoe sole heel - rigid foam pad - pressure sensor - protective layer - shoe cover, were demonstrated in two control experiments. Among them, for example... Figure 7 As shown, in control experiment A, the following was performed: Figure 2 The sensing unit shown removes the rigid foam pad 104 and the protective film 102, and the top surface of the pressure sensor 103 is directly attached to the bottom of the shoe 106. In Control Experiment B, the pressure sensor 103 is directly and separately embedded in the heel position of the inner sole of the shoe 106. Ultimately, the sensing unit of this invention, Control Experiment A, and Control Experiment B each collected standard pressure values ​​acquired by the pressure sensor in the same walking cognition experiment. The data and visualization results are as follows: Figure 8 , Figure 9 and Figure 10 As shown. Plantar pressure versus standardized pressure value. (Range 0–255) shows a negative correlation, meaning that as pressure increases... The value decreased. Figure 8 When the sensing unit of the present invention is used, when the sole of the foot is suspended in the air, The value is close to 255, with virtually no interference pressure; while if Figure 9 If the pressure sensor is directly attached to the sole of the shoe, the pressure data may be distorted due to poor adhesion. Figure 10 The solution of embedding pressure sensors in the middle of the shoe during the suspension phase The value is approximately 200, indicating significant interference. In comparison, the five-level sandwich structure sensing unit proposed in this invention experiences the least irrelevant pressure during the foot-suspended phase, enabling more accurate acquisition of real pressure changes during walking. This represents the optimal solution currently available.

[0085] The embodiments described above are merely some preferred implementations of the present invention and are not intended to limit the invention. Those skilled in the art can make various changes and modifications without departing from the spirit and scope of the invention. For example, the Arduino Due can be replaced with an Arduino Uno R3, the 1kHz sampling rate in the Arduino Due can be dynamically set as needed, and so on. Therefore, all technical solutions obtained by equivalent substitution or equivalent transformation fall within the protection scope of the present invention.

Claims

1. A real-time sound feedback device based on gait event triggering, characterized in that, Includes sensing units, lower-level machines, upper-level machines, and sound transmission systems; The sensing unit includes a pressure sensor, a shoe cover, and a rigid foam pad. The shoe cover is used to cover the sole of the test subject's shoe. A protective film is attached to the inside of the shoe cover at the position corresponding to the heel. The top surface of the pressure sensor is attached and fixed to the bottom of the rigid foam pad. The area of ​​the rigid foam pad not covered by the pressure sensor is fixed to the shoe cover. During the test subject's walking, the heel rhythmically applies pressure to the rigid foam pad. During the heel strike, the sensing area of ​​the pressure sensor and the protective film maintain a detachable pressure contact. The lower-level machine is connected to the pressure sensor in the sensing unit and the upper-level machine respectively; the lower-level machine collects the voltage signal output by the pressure sensor in real time, maps it to a standard pressure value with a value range of [0,255] and transmits it to the upper-level machine in real time, and the upper-level machine is connected to the sound transmission system. The sound transmission system is worn on the ears of the test subjects and has sound insulation and sound transmission functions; The host computer analyzes the received standard pressure data stream and uses the latest collected standard pressure value falling within the pressure response range corresponding to the heel strike event as the first judgment condition. The second judgment condition is that the difference between the average standard pressure in the most recent time window and the average standard pressure in the previous time window is less than a negative threshold between -1 and -5. When both judgment conditions are met, it is determined that a heel strike event has occurred, and the host computer immediately controls the sound transmission system to emit sound stimuli with a preset frequency, amplitude, and duration.

2. The real-time sound feedback device based on gait event triggering as described in claim 1, characterized in that, The pressure sensor is a piezoresistive pressure sensor, whose output voltage signal is negatively correlated with the applied pressure. After the lower-level computer collects the voltage signal output by the pressure sensor in real time, it standardizes and maps it into an 8-bit binary standard pressure value, and then transmits it to the upper-level computer in real time in the form of a binary data stream.

3. The real-time sound feedback device based on gait event triggering as described in claim 2, characterized in that, In the first determination condition, the lower limit of the pressure response range is 215~230, and the upper limit is 240~255.

4. The real-time sound feedback device based on gait event triggering as described in claim 2, characterized in that, The time window size in the second determination condition covers 3 to 8 standard pressure value data points.

5. The real-time sound feedback device based on gait event triggering as described in claim 1, characterized in that, The sound transmission system consists of a sound card and noise-isolating headphones. The host computer sends instructions to the sound card, which then drives the noise-isolating headphones to emit sound stimuli with preset frequency, amplitude, and duration.

6. The real-time sound feedback device based on gait event triggering as described in claim 1, characterized in that, The outer surface of the shoe cover that contacts the ground is made of sound-absorbing material.

7. The real-time sound feedback device based on gait event triggering as described in claim 1, characterized in that, The lower-level machine communicates with the pressure sensor, the lower-level machine communicates with the upper-level machine, and the upper-level machine communicates with the sound transmission system via wired transmission.

8. The real-time sound feedback device based on gait event triggering as described in claim 7, characterized in that, The lower-level computer, upper-level computer, and sound transmission system are all integrated into the backpack. The lower-level computer and the sensing unit are connected by a retractable cable, and an ergonomic cable routing scheme is used to eliminate cable entanglement interference during walking.

9. The real-time sound feedback device based on gait event triggering as described in claim 1, characterized in that, It also includes a head-mounted EEG acquisition device that communicates with the host computer, used to collect EEG signals from the subject during walking.

10. A method for collecting walking cognitive experimental data using a real-time sound feedback device based on gait event triggering as described in any one of claims 1 to 9, characterized in that: The shoe cover from the sensing unit was placed over the sole of one of the subjects' shoes, and the head-mounted EEG acquisition device was worn on the subject's head. During the walking process, the heel rhythmically applied pressure to the rigid foam pad, and the sensing area of ​​the pressure sensor and the protective film maintained a detachable pressure contact during heel strike. The lower-level computer collects voltage signals in real time, processes them into a standard pressure data stream, and then transmits it to the upper-level computer for storage and analysis. During the subject's walking process, the host computer detects the occurrence of a heel strike and immediately controls the sound transmission system to execute corresponding sound stimuli according to the frequency, amplitude, and duration specified in the preset auditory stimulation paradigm. Simultaneously, during the subject's walking process, the head-mounted EEG acquisition device collects the subject's EEG signals in real time and stores them synchronously in the host computer.

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